Blade pitch control mounted on propeller hub



Dec. 20, 1955 N. R. RICHMOND 2,727,579

BLADE PITCH CONTROL MOUNTED 0N PROPELLER HUB Filed March so. 1949 sSheets-Sheet 1 In were 30 [liaison llz'c& mama? Dec. 20, 1955 N. R.RICHMOND BLADE PITCH CONTROL MOUNTED ON PROPELLER HUB Filed March 30,1949 3 Sheets-Shget 3 w Mm\ IIIIIIIIIIII/IL Invewioz liaisonR.Rz'c%maua2 197M 5 fliioa ney United States t ntio BLADE PITCH CONTROLMOUNTED N PROPELLER nun Nelson R. Richmond, Thompso'nville, Conm,assi'gnor to United Aircraft Corporation, East Hartford, Comn, acorporation of Delaware Application March 30, 1949, Serial No. 84,269 6Claims. (Cl. 170 -1601) This invention relates to an improved propellerconstruction and particularly to an improved self-contained propellerhaving the propeller controls supported on a non-rotating supportjournalled on the propeller hub.

An object of this invention is a propeller-control uhit including apropeller-carried non-rotating control system.

A further object is a propeller-control unit including means foraccurately positioning the control system with respect to the propeller.

A still further object is a non-rotating hydraulic control systemincluding a governor and pump journalled on a propeller hub.

Other objects and advantages will be apparent from the specification andclaims, and from the accompanying drawings which illustrate what is nowconsidered to be a preferred embodiment of the invention. 1

Fig. 1 is a side view partly in section of the improvedpropeller-control unit.

Fig. 2 is an end view, partly in section, of the control unit, lookingaway from the propeller.

Fig. 3 is a schematic diagram of the propeller pitch changing mechanism.

Fig. 4 is an end view of the outerbeariiig race of the transfermechanism and control. unit support.

Fig. 5 is a section showing means for attaching the outer bearing raceof the transfer mechanism to the control unit casing.

The propeller-control unit disclosed in this application is animprovement in the construction shown in' Erle Martin Patent No.2,619,182, issued November 25, 1952. The propeller structure issubstantially the same as that shown for the inboard propeller of PatentNo. 2,619,182. The controls are also substantially the same as thecontrols in that application but in the present construction thecontrols are mounted directly on the pr opellei hub so as to form withthe propeller a unitary propeller-control.

unit which may be assembled on and removed from the propeller shaft as aunit and may therefore be com pletely assembled and adjusted on thebench or in' the shop before being mounted on the airplane and whichwill not require adjustment as part of the procedure of installing thepropeller on the airplane. Another advan tage of the presentconstruction is that by mounting the controls on the hub of thepropeller, the controls" will move with the propeller in its axialmovements caused by thrust, etc., and such movements will not aifect therelation. between the control and: the propeller so as' to cause achange in propeller pitch andthus adversely affect the governing andpitch control. Although a unitary propeller-control unit is provided;the advantages of a stationary control and a stationary oil reservoirare retained.

As shown in-the accompanying drawings-, thepr'op lei coritrol unitcomprises apropelier indicated ge erally at 1'0 and a control unitindicated generally; 12. The pro. peller-control unit is n't'ou'ritd asa litiit on a pr dpeller 2 shaft 14 supported in and driven by an engineindicated generally at 16. The propeller which is substantially the sameas the inboard unit of the dual rotation propeller shown in Erle MartinPatent No. 2,619,182, referred to above, comprises a hub 18 having aninboard extension 20 mounted on shaft 14 and positioned by the usualcones 22 and splines 24 for rotation about the propeller axis 26. Blades28 are rotatably mounted in hub 18 for pitch changing movement and areactuated in their pitch changing movement by a vane motor 30 havingrelatively movable parts, with one part secured to the propeller hub andthe other part secured to the propeller blade and located in the shankof each propeller blade as set forth in more detail in Patent No.2,533,415 referred to in Patent No. 2,619,182. Hydraulic fluid is pumpedfrom a sump 32 mounted on and rotating with the hub 18 by pumps 34 intoa conduit 36 leading to a follow-up valve indicated generally at 38.Pumps 34 are carried by and rotate with hub 18 and are actuated by anormally stationary cam 40 carried on one end of a sleeve 42 to increasethe pressure of the hydraulic fluid and supply this pressure fluid tothe follow-up valve 38 also carried by and rotating With hub 18. Fluidis led from valve 38 through suitable conduits 44 and 46 to the vanemotor 30. Valve 38 is so constructed that when pressure fluid issupplied to one side of the vane motor, say through conduit 44, theother side of the vane motor is connected through valve 38 with the sumpor reservoir 32 to permit oil to drain from that other side.

The several blades 28, there being four in the propeller shown in Figure1, are geared together by a connecting gear 48 for equal andsimultaneous pitch changing movement. A follow-up mechanism indicatedgenerally at 50 is gear driven from connecting gear 48 and serves toposition one part 52 of the two-part follow-up valve 38 in accordancewith the pitch of the propeller. The other part 54 of the two-part valve38 is positioned by control mechanism described below. Due to thefollow-up feature of this valve, each position of valve part 54 definesa colresponding propeller pitch when the valve is in a neutral position,i. e., when the valve is not introducing fluid to either side of thevane motor 30 to change the pitch of the propeller. An extension 56 ofvalve part 54 is positioned by a stationary thrust plate 58. Extension56 being carried by the propeller hub slides around the face of thrustplate 58 as the propeller rotates.

Hub extension 28 has a sleeve 60 carrying a gear 62 pinned to theinboard end by means of a pin 64. Sleeve 42 is rotatably mounted on theinboard extension 20 by roller bearings 66 and 58. Sleeve 42 is heldagainst axial movement relative to hub extension 20 by segmental shoes70 fitted into slots in sleeve 60 and sliding in a groove 72 in theinner surface of sleeve 42. Sleeve 60 being pinned to shaft 14 thussecures sleeve 42 against axial movement. The entire control mechanism12 is mounted, by means that will be presently explained, on sleeve 42and is, therefore, rotatably mounted on the hub 18 and held againstaxial movement with respect to the hub. The control mechanism comprisesa casing 74 on which the various control elements such as the governorindicated generally at 76, the auxiliary motor indicated generally at78, the servomotor indicated generally at 80, the solenoid packsindicated generally at 82 and the reservoir and pumps indicatedgenerally at 84 are removably mounted. Casing 74 is provided withupstanding lugs 86 forming a slot between them. A lug 83 secured to theengine nose is located between upstanding lugs 86 when the propeller isassembled on an engine so that lug 88, while permitting relative axialand radial movement of casing 74 with respect to the engine nose, will74 about the propeller axis 26.

prevent rotation of easing. If desired, some resilient.

material such as rubber may be inserted between lugs 86 and 88 toprovide a more resilient connection. The control mechanism includes agovernor 76 having the usual speeder spring 77 which may be adjusted byany suitable means such as manually by a pulley or as shown in Figure 2,by an electric motor 90. The usualflyweights, not shown, which arebalanced against the speeder spring actuate governor valve. 92 tocontrol the flow of fluid to and from servomotor 80. Hydraulic fluidwhich is carried in a reservoir 94 is pumped therefrom and placed underpressure by pump 96 driven by gear 62 by relative rotation of thepropeller and casing 74. This pressure fluid is led through conduit 98to the usual relief valve, not shown, and through conduit 100 to thegovernor valve 92. Governor valve 92 serves to selectively connectconduit 102 with pressure line 100 or with a drain to the reservoir 94.Conduit 102 is connected through normally open solenoid valve 104 withthe chamber 106 of servomotor 80 to thereby move the servomotor and rack108 under the influence either of pressure fluid 106 or the spring 110at the opposite end of rack 108. Rack 108 meshes with gear 112 carriedby an inner race 114 of a ball bearing indicated generally at 116. Theouter race 118 of the ball bearing 116 is secured to control casing 74by screws 121 as shown in Figure 5. In a manner which will be laterdescribed, movement of inner race 114 will move thrust plate 58 toeffect the change in propeller itch.

p As described above, outer race 118 is secured to control casing 74.Outer race 118 is mounted on sleeve 42 to normally hold the controlcasing 74 in a fixed position with respect to sleeve 42 whilepermitting, under a selected condition, relative rotation of controlcasing 74 and sleeve 42. This mounting of control casing 74 on sleeve 42is effected by means of small rolls 120 journalled on an axle 122secured in a depending boss on the ring 118. As shown, there are fourrollers 120 arranged around the outer race 118. If desired, more rollersmight be added. Rollers 120 are given a rounded contour to fit a groove124 in the outer surface of sleeve 42. These rollers are made a snug fitin the groove 124 so as to hold control casing 74 on sleeve 42 withoutany appreciable movement therebetween. Normally, casing 74 and sleeve 42are held against relative rotation but under certain conditions such asfeathering and unfeathering, which will be later described, it ispossible to rotate sleeve 42 with respect to casing 74 at which timerollers 120 will roll around sleeve 42 in groove 124. By thus securingcasing 74 against axial or radial movement with respect to sleeve 42,casing 74 is positioned with respect to hub extension 56 thussubstantially limiting any relative axial movement between the controlmechanism and the hub which would adversely affect the governing and thepitch control.

Inner race 114 carries rolls 126 which operate in axially extendinggrooves 128, in a sleeve 130, telescoped with race 114 and having anupstanding thrust plate 58 at one end thereof. Rolls 132, rotatablymounted on axles fixed on outer race 118, operate in angularly arrangedgrooves 134. The axles of rollers 132 are therefore held stationary withrespect to housing 74 so that actuation of inner race 114 by rack 108will, by means of roll 126, rotate sleeve 130. Rotation of sleeve 130will cause axial movement thereof, as angularly arranged groove 134passes fixed roller 132. Axial movement of sleeve 130 and thrust plate58 carried thereby will axially move valve extension 56 to change thepropeller pitch. The mechanism thus far described will, therefore,maintain constant speed of the propeller driving engine by the action ofthe governor valve 92 controlling the position of the rack 108 by meansof the servomotor 106 and thus by controlling the position of thrustplate 58 and the inner part 54 of the valve 38 will adjust the propellerpitch to maintain a preselected speed.

A gear 136 on the inboard end of sleeve 42 meshes with a gear 138 whichis operatively connected with the auxiliary motor 78. Fixed to gear 138is a ratchet 140. A pawl 142 cooperates with ratchet of gear 138 toprevent rotation of gear 138 in one direction. Rotation of the propellercarried pumps about cam 40 tends to rotate sleeve 42 and gear 136therewith. Rotation of sleeve 42, cam 40, and gear 136 in thatdirection, however, is prevented by gear 138 and the pawl and ratchet140 and 142. Sleeve 42 is, therefore, fixed against rotation with thepropeller.

Provision is made for disconnecting the propeller governor from theservomotor and manually controlling the position of the servomotor bymanually controlling the flow of oil into and out of the servomotor.This manual control is provided by solenoid actuated valves 144 and 146which are normally closed. In order to manually increase the propellerpitch, the solenoid of valve 104 is actuated to close valve 104 therebyblocking further control by the governor 76. If nothing further is done,oil will be locked in the servomotor and the propeller held at thismanually selected pitch position. In order to increase the propellerpitch as in feathering or unreversing a solenoid is actuated to openvalve 146 and allow oil to drain from chamber 106 through conduits 148,150, and 152 to reservoir 94 as spring pushes the servomotor piston andrack to the left as viewed in Figure 2. Switches, not shown, may also beclosed to actuate solenoid 154 to withdraw stop 156 and to actuateauxiliary motor 78. Actuation of auxiliary motor 78 will tend to rotatecam 40 and supply pressure fluid to the propeller as it slows down inapproaching the feathering angle. To reduce the pitch as in reversing orunfeathering valves 104 and 146 remain closed and valve 144 may beopened, by manual actuation of a switch not shown, to introduce fluidunder pressure from conduit 98 through conduit 148 to chamber 106 of theservomotor 80. This will move rack 108 to change the position of innerpart of valve 38 and thus change the propeller pitch.

The actual arrangement of the electrical circuits and switches foractuating the several solenoids and the auxiliary motor have beenomitted for purposes of simplicity and because it is believed that theinvention can be readily understood without further description thereof.Reference may be had to application Serial No. 609,843, now Patent No.2,619,182, however, for a further detailed description of theseelectrical circuits.

An auxiliary pump 158 is driven from gear 136 through gear 160. Thisauxiliary pump is normally stationary but is actuated whenever theauxiliary motor 78 is operated, to supply pressure to line 162 tothereby supply pressure fluid for the actuation of the servomotorwhenever the propeller is not operating. Rotation of the propellerrotates gear 62 pinned to the inboard end of hub extension 20. A gear164, Figure 2, meshes with gear 62 and is actuated thereby. Gear 164 isgeared to the governor to drive the governor by rotation of thepropeller. Gear 164 also drives pumps 96 for supplying pressure fluid tothe governor. It will, therefore, be apparent that when the propellerstops rotating, it is necessary to have an auxiliary pump to supplypressure for operating the servomotor 80.

Control casing 74 terminates adjacent to the nose of engine 16 but itsonly connection with the engine is by means of lugs 86 and 88. Ifdesired, a flexible boot or shield 166 may be placed over the jointbetween the engine and the control member to seal this opening.

It will be apparent that the above described structure provides apropeller-control unit which may be placed on or removed from thepropeller shaft as a unit and in which the control mechanism ismaintained stationary but is journalled on the propeller hub and heldagainst axial movement relative to the propeller hub. It will also beapparent that the only connections necessary to connect the manualcontrols at the control station with the control unit of the propellerincident to installing the'propeller on a propeller shaft will be tolocate lug 88 between lugs 86 and make the necessary electricalconnections which may be made by the well known separable plugconnections schematically indicated by the block 168. It will also beapparent that the propeller is a self-contained hydraulically actuatedpropeller having its own pumps and reservoirs and deriving its power foractuating the pumps by the rotation of the propeller except for theextra range operations where the power is derived from the airplaneelectrical system.

It is to be understood that the invention is not limited to the specificembodiment herein illustrated and described, but may be used in otherways without departure from its spirit as defined by the followingclaims.

I claim:

1. In combination, a propeller hub, including hydraulic pitch changingmechanism and a pump for supplying hydraulic fluid under pressuretherefor, and having an axially extending projection concentric with thehub axis, a bearing sleeve rotatably supported on and concentric withsaid projection, means carried by said sleeve for actuating said pump byrotation of said propeller, a control housing supported on said sleeve,means preventing relative rotation of said housing and said sleeve,means restraining said housing against rotation, control mechanismcarried by said housing including a reservoir, a pump, a servomotor anda control therefor, means carried by the propeller hub driving said lastmentioned pump by rotation of said propeller hub to draw liquid fromsaid reservoir and direct it to said servomotor control, and meansoperatively connecting said servomotor with said hydraulic pitchchanging mechanism.

2. A unitary propeller control assembly comprising a propeller unitincluding a hub, blades and hydraulic pitch changing mechanism rotatableas a unit, a stationary control unit including a housing supporting areservoir, a pump, and governor mechanism, means rotatably supportingsaid stationary control unit on said hub comprising an elongated sleeverotatably supported on bearings on, and concentric with the axis of,said hub and means supporting said control unit on said sleeve, andaxially positioning said control unit with respect to said sleeve, meansfor preventing rotation of said control unit and said sleeve with saidpropeller and means operatively connecting said governor mechanism withsaid hydraulic pitch changing mechanism.

3. In combination with a controllable pitch propeller havinghydraulically actuated pitch changing mechanism and a support rotatablewith said propeller, a stationary control unit comprising, a casing,hydraulic control mechanism supported on said casing and operativelyconnected with said hydraulic pitch changing mechanism, a bearingrotatably supporting said casing on said support, means permanentlyrestraining said casing against rotation with said propeller, and meansactuated by relative rotation of said support and said casing forsupplying hydraulic fluid under pressure to said hydraulic controlmechanism and said hydraulically actuated pitch changing mechanism.

4. A device as claimed in claim 2 in which the hydraulic pitch changingmechanism includes an entire hydraulic motor and means for conductingoperating fluid to and from said motor.

5. A device as claimed in claim 4 in which the hydraulic motor hasrelatively movable parts, one of which is connected to the propellerblades and the other of which is fixed to the hub.

6. A device as claimed in claim 3 in which the hydraulically actuatedpitch changing mechanism includes a hydraulic motor and a pump forsupplying pressure fluid to said motor rotatable with said propeller andin which the means actuated by relative rotation of said support andcasing includes said pump.

References Cited in the file of this patent UNITED STATES PATENTS2,364,672 Stevenson Dec. 12, 1944' 2,467,964 Carson et a1 Apr. 19, 19492,476,638 Stuart III et al July 19, 1949 2,640,555 Cushman June 2, 1953FOREIGN PATENTS 407,697 Italy October 1946 580,923 Great Britain Sept.26, 1946

